Incandescent lamp.



R. MONEILL. INGANDES'GENT LAMP.

APPLICATION FILED MARIQ, 1908.

Pafentao June I, 1909.

PATENT OFFICE.l

RALPH MCNEILL, OF NEW YORK, N. Y.

INCANDE SCENT LAMP.

Specification of Letters Patent.

Patented June 1, 1909.

Application filed March 19, 1908. Serial N o. 422,162.

i nected to leading in wires sealed in the tube.

The invention has for its object to provide improvements in the manner of connecting the filament' to the leading in wires, so as to permit of the filament being inserted linst prior to the final exhaustion and sealing of the tube, which is not now possible.

The tubular lamps now on the market have the filaments permanently connected to the leading in wires, before insertion into the. I

tube, after which the leading in wires must be properly centered and sealed at each end,

land then the lamp is exhausted through a 'tube left for this purpose, and finally sealed by melting off the tube.A As will be seen, such lamps undergo considerable handling after the filament is inserted and the wires sealed in, so that breakages frequently occur between the filament and the leading in wires, in the filament itself, or the ends of the leading in wires may break off, rendering theA lamp worthless. Such breakage is especially likely to occur at the joint between the fila# ment and the leading in wire, which is usually a lap oint surrounded by carbon, either deposited" by decomposing a hydrocarbon, or

cementer by a mixture commonly' composed of graphite and burnt sugar for a binder, which carbonizes when' the current is turned on. The deposited joints are expensive to make, and the process involves considerable fire risk, so that there are restrictions upon its use, and the cemented joint is largely used at the present time. Such a joint is, however, soluble, and the presence ofmoisture tends to weaken it to such an extent that the tension of the filament breaks it. The moisture from the breath of the glass blower in sealing the leading in wires frequently causes such breakage, and atmospheric moisture may do the same thing. As such lamps commonly have kanchors or intermediate supports for l the filament which are customarily inserted after the filament is inserted, an additional possibility of breakage presents itself. As a consequence, the number of defective lamps considerably increases the cost of production.

According to this invention, I have devised a. novel manner of detachably connecting the filament and the leading in wires, whereby the leading in wires can be inserted and sealedindependently of the filament, and the filament inserted just before the tube is finally exhausted and sealed, after all the other operations have been completed. By means of this improvement, I have devised a novel method of making an incandescent lamp, whereby the loss in manufacture will be reduced, and also the cost. Furthermore, by this invention a new filament can be easily substitutei'l for a broken one without requiring splicing, disturbance of the leading' in wires, or shortening of the filament. It is possible to carry out the invention by reason of the fact that in lamps of this class, the filament is under a certain amount of tension when cold, which maintains the filament tant when it is heated, and the invention is illus` trated herein in connection ith yarious -means for exerting a tension on the filament and thereby always securing good Contact at the detachable Connection between the filament and the leading in wires.

employ supports or"anchors for supporting the intermediate portions of the filament, and this invention further has reference to an improved form of anchor for this purpose, 'which will lic-cheaper to make and insert than those in common use, and equally effective.

The inventionwill be more fully understood in connection with the description of the accompanying drawings, wherein-- -ligure l is a view of a lamp embodying the invention and made according to the method thereof, Fig. 2 is a view showing a lamp in shows a slightly modified leading in wire, Fig. 4 shows the invention applied to a form of lamp wherein the leading in wire exerts the tension onthe filament, Fig. 5 shows a modified form of tension device embodying the invention, and 'Fig'. 6 shows a further modification.

leferring first to the features ofconstruetion, 1 re )resents a [dass tube which is cut off in pre etermined I engths and then drawn In lamps of this 'class it is customary to lUU condition for exhaustion'and sealing, Fig. 3

' wires are looped or coiled so as to interlock down at the ends 2, 3, leaving adjacent one end, as 2, in Fig. 2, a small projectingr tube 4, through which the filament 5 is inserted, and also to permit the attachment of a, pump for exhausting the interior, the tube 4 being then sealed between the pump and the main tube 1 to hold the vacuum.

"7, S represent leading in wires, which are respectively sealed in the tube 1 after vthe ends are drawn down and the anchors` inserted, if the latter are used. A feature of novelty resides in the fact that the leading in with the filament when inserted, either having a hook, or eye 9, as in the right hand end of Fig. 1, or as the wire S, at the left hand end of Fig. 1. lt will be understood thatI in ractice both ends will be alike though such l tension. 1n Fig. 5 is shown a coil 13 in one or both of the leading in wires, for the same with the glass is not necessarily the ease. As is well undcrstood, the leading m wires are usually made Vof platinum, and the ends sometimes break` off close to the glass, so the form 8 has an advantage in that if one end breaks the other end can be used for connecting with the ferl rule or socket, and thence to the line Wires. Also thetube or tip 4 can be at the end bei tween the wires, thereby reducing the liabil ity of breakage when sealing. Such lamps ordinarily have the filament under tension in order to prevent its sagging by reason of cX- pension, when heated, the tension being prouced in F'gs. 1, 2 and 3 by a coil 10 in the filament itself.

In Fig. 4, the leading in wires 12 are made as springs tending to hold the filament under purpose. It will be understood, however, that my invention is not restricted to a lamp wherein the filament is under tension, since it may be sup orted to lprevent contacting by other means than'tension,

as by anchors as in Fig. 1.

ln 6, is shown a modification, wherein the leading in wire is sealed in a tube, which tube is sealed in the main tube 1. In this form the flared end of the small tube aids the laster to hold the end ferrule in place. Eac end of the tube also has a socket or fer-'rule 14, covering the ends, and enabling connection to be made with the line wires as I is well understood.

A further feature of the invention resides in the provision of an anchor or intermediate support 15, formed of a wire having an eye or loop 16 through which the filamcnt'passes, and a plurality of extensions 17, 18, to bear on the inner surface of the tube 1, thereby forming a support for the filament. The anchor or intermediate 'support 15 shown on the right hand side of tube 1 in Fig. l comi rises a member having an eye or loop 16 to 'i e engaged by the filament 5, and extensions 17, 18, having a transverse portion bent Q which foot frictionally or yieldingly 'engages the inner surface of the tube 1, thereby positioning anchor 15 in tube 1 and also preventing anchor 15 from upsetting in tube 1. Obviously any number of extensions 17, 18 with transverse feet can be provided for anchor 15. The similar anchor 15 shown on the left,- hand side of tube 1 in Fig. l comprises a central portion having an eye or loop 16, one end of said central portion being bent to form a foot 18 which engages the inner surface of tube 1, the other end is joined to a curved portion which conforms approximately to the linner surface of tube 1, said curved portion having a foot 17V bent lengthwise in the direction of the tube 1. The feet 17 and 18 as in the other type of anchor 15, serve to prevent anchor 15 from upsetting. ln lamps of this type, the intermediate. supports, where used, are commonly formed of short glass rods, having a loop or eye, usually of wire, al the end, and blown into the tube. This is an expensive process and by this invention, the anchors can be much more cheaply made,

and inserted before the filament, and are equally effective when once in place.

To connect the filament with the leading in Wires, bent wires 19, preferably of nickel, are em loyed which are cemented to the ends ofthe ilament by cement 20, thc joints being made by lapping the ends of the filament and the intermediate wires and either depositingr carbon. from a fluid hydrocarbon by passing` an electric current, or by carbonizing a paste composed of graphite and caramel. The deposited joint is expensive, and involves a fire risk, so its use is 1n many places prohibited, and the cemented joint is commonly used. The cement is, however, soluble in water, and such joints between the lament and the leading in Wires in lamps made according to processes heretofore practiced, frequently break because of moisture, or in the necessary operations of completing the lamp.

j splice, or the leading in Wires break. After a filament is permanently connected with thc leading in wires in processes heretofore known, considerable glass blowing is done, such as inserting the anchors, sealing the leading in Wires, and the final sealing. It has frequently ha pened that the moisture in a glass blowerslbreath has so softened the joint, that it would give way. These difficulties are obviated with this invention, because the filament is inserted last, just before drying, exhaustion, and sealing, and the tension or anchors, or both, maintain the eleclengthwise relative to tube 1 to form a foot, i trical contact. Furthermore, the detachlill ably connected filamentpermits of renewal Modifications and changes in the specific details herein described may be made Without departing from the scope of the invention.

Having thus described my invention, I declare that what I claim as new and desire to secure by Letters Patent, is

l. An incandescent lamp comprising. a tube having leading in Wires sealed at each end, each of said Wires having a bent portion, a filament having means at its respective ends for removably engaging the bent portions of the leading in wires, saidl lament being coiled so as to exert a tension on the ilament at said connections with the leading in Wires.

2. An anchor for a stretched filament comprising an eye portion, an extension connected therewith adapted to yieldinglyengage the interior of a tube.

3. An anchor for a filament inclosed in a tube having a portion for engaging the lament and another portion connected With said rst named portion for frictionally engaging the interior Wall of the tube at a plu- Y rality of points.

4. An anchor for a filament inclosed in a tube having a portion for engaging the filament and another portion adapted to yieldingly engage an'inner wall of the tube at separated points, said latter portion including a foot member.

5. An anchor for a filament inclosed in a tube having an eye member for engaging the filament, and extensions from said eye member having a portion thereof positioned to vyieldinglyv engage the inner surface of the tube at separated points.

In testimony whereof I afiiX my signature, in presence of two Witnesses.

RALPH MCNEILL.

Witnesses:`

JULIAN S. WoosTER, GEO. O. HOFFMAN. 

